Polysiloxane-based automotive protectants are now established products in the marketplace. By the term "automotive protectants" is meant those products which are applied to vinyl, leather, plastics, rubber, and other visible surfaces of automobiles, trucks, and other vehicles to improve the gloss of such surfaces, and also to protect such surfaces from the damaging effects of sunlight, heat, moisture, etc. Although described as "automotive protectants", the term "automotive" is not meant as a restriction on the use of these compositions, which may be equally useful on boats, trains, planes, outdoor furniture, etc., and also for a variety of interior uses. Protectant compositions are generally not applied to textiles, nor to glass or painted surfaces, the latter of which tend to have a greasy appearance if so treated. The term "automotive" is descriptive of the market where such products first evolved, and which remain the largest market.
In use, automotive protectants are applied to a substrate desired to be "protected" such as a car seat, dashboard, arm rest, etc., and rubbed with a cloth. The protectant may be sprayed directly onto the surface to be treated, or may be first sprayed onto a cloth, pad, or the like. As a result of this application, the gloss of the substrate is enhanced considerably. Evaporation of the aqueous continuous phase leaves an organopolysiloxane coating which may, in some cases, penetrate polymer substrates, ameliorating loss of plasticizers from such surfaces due to exposure to sun and heat. The protectants are often formulated with UV absorbers as well, and the net effect is not only a restoring of the "as new" look to the vehicle or other product, but also in a general prolonging of life of substrates, e.g. dashboards to which the protectant has been applied.
While lotion and paste-type protectants are available, these have not met the acceptance of sprayable formulations, due not only to their increased difficulty in application to the surface, but also due to their propensity to leave a buildup of protectant at seams, crevices, and on highly textured surfaces such as crushed leather-like vinyl. Examples of such paste and lotion-type protectants are provided by U.S. Pat. No. 5,433,890, wherein protectants containing both an amino-functional organopolysiloxane and a polydimethylsiloxane, a film forming polymer to increase abrasion resistance, and morpholine, necessary to activate the film forming polymer are disclosed. These protectants must be left on the surface for a considerable period before wiping off the excess, and maximum effectiveness is achievable only with a second coating. The disadvantages of such preparations are readily apparent.
In Canadian published application CA 1,176,828, paste-type, organopolysiloxane emulsion-based polishes which contain a silicone-soluble UV absorbent are disclosed. These polishes have a high proportion of organo-polysiloxane, greater than 20 weight percent solids, and an organic thickening agent which provides the paste-like character of the polish and serves to maintain the high level of silicone solids uniformly dispersed. However, these compositions are not sprayable, and therefore suffer the drawbacks of other pastes, creams, and lotions. Moreover, they contain a high proportion of relatively expensive organopolysiloxane.
The active ingredients of automotive protectants are organopolysiloxanes. Organopolysiloxanes are relatively expensive, and a typical protectant may contain from 20 weight percent to 40 weight percent organopolysiloxane as an aqueous emulsion. Non-aqueous preparations containing organic solvents or aqueous preparations containing dispersed organic solvents are undesirable both due to the lingering odors associated with these solvents, but also on environmental grounds. Despite the relatively high amount of organopolysiloxane, studies demonstrate that only a relatively small amount, i.e. 10% to 20% of what is applied, actually ends up on the substrate. It would be desirable to be able to lower the amount of organopolysiloxane in automotive protectants without lowering performance, or to obtain increased performance at the same level of active ingredient. Even with the same organopolysiloxane content, improved performance may allow the application rate to be lowered, resulting in greater economy to the purchaser.